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Community and Q&A

Your opinions on my 1955 brick ranch?

SlateRun | Posted in Energy Efficiency and Durability on

Hi, I’m looking to develop a plan as to how to convert my recently aquired home into a comfortable, reasonably energy efficient place to spend the next few decades.

here is the overview.

The place is relatively small, two bed, one bath, about 1200 sq. ft. It is constructed on a full basement walls of eight inch block. There is no insulation in the basement. The exterior walls of the first floor are 1/2″ plaster over 1/4″ rock lath. The lath is attached to 3/4″ furring over 4″ block, with an exterior layer of 4″ red brick. The ceilings are also rock lath and plaster on typical 2×6 ceiling joists. The ceiling insulation is nearly non-existent, with areas of original 2″ fiberglass batting encased in Kraft paper “pillows”, and random applications of unfaced r-19 glass batts. Another challenge is the ceiling itself, as it is about a holey as a screen door. At some point, decades ago, central air was added, and it’s a textbook case of what not to do. The attic is a spaghetti mess of 8″ flex duct blasted everywhere. There are 14 ceiling grilles for feed and returns. The flex is at least two decades old and falling apart, the box plenums, and inside/outside units are only three years old. On a 90* day the system really struggles to keep the interior cool. The most recent owner was a big fan of recessed can lighting and added ten of them to different rooms. The roof is ventilated with continuous ridge vent and gable end vents. Soffit venting would be a challenge as there are huge soffits, 3-7′ deep that were originally unvented, and covered with painted bead board, then recovered with aluminum soffit panels.

Obviously the issues include a ton of air infiltration. There is a stack effect with air moving behind the exterior plaster, from the basement up to the attic. All windows are vinyl replacements that are of varying ages. A lot of the windows are fixed glass, with big banks of tall vertical casements, ganged in groups of 3 to five, with every other one operable. The doors are original, with a bit of brass weatherstrip, but tons of leakage. The previous owner’s reported an average of a thousand gallons of oil burned per year, and that was AFTER a new 87% efficient furnace was installed a few years back. Oddly the near lack of insulation didn’t phase them, as they chose to add a $5000+ coal stove set-up to make the place warm enough to occupy without spend $3K on oil. They also switched from a summer/winter hook-up to a GE heat pump HWH. The coal stove is gone.

The house is a real special place, it is full of character, with hardwood floors throughout, plaster in great shape everywhere, and a ton of light from all the windows that give it a funky mid-century vibe. I have no intention of getting crazy and demoing anything in the name of better energy efficiency, It is located in a 4A zone, a few miles from the Maryland/PA border

So, after all this, my question is simple. What would you do, and how would you do it? Spray foam the rafters to make a hot roof. Get rid of the AC disaster and go with a few split systems? Spray foam the cellar walls?

Thanks.

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Replies

  1. Steve Knapp CZ 3A Georgia | | #1

    Air sealing would be a good first step. This thread includes some links and information that can help you to begin considering how to go about it. https://www.greenbuildingadvisor.com/community/forum/passivhaus/102081/air-sealing-guide

  2. Bennett G. | | #2

    I'm in agreement with Steve. With the house you describe and assuming you're not up for ripping out the entire interior, air sealing the building envelope seems like step 1. I found this EPA guide a pretty good overview: https://www.energystar.gov/ia/partners/publications/pubdocs/DIY_Guide_May_2008.pdf

    Next, I would replace the HVAC ducts with the best you can find - R-8? and seal the duct system up.

    Third, I would blow cellulose into the attic up to code or better. Thinking ahead, I'd cut in soffit vents, install insulation baffles and close off the gable vents so you get good thermally driven ventilation from soffit to ridge.

    If you're a DIY guy, I'd consider making a blower window: http://www.builditsolar.com/Projects/Conservation/BlowerDoor/BlowerDoor.htm ( BuildItSolar is a great resource for DIY energy efficiency ideas. ) Running a blower to pressurize or depressurize your envelope will be very helpful during air sealing to find leaks in your envelope and ductwork once you've sealed up all the obvious places.

    Once you've done all that, consider solar screens to cut the insolation in summer and insulating shades for winter for all those windows.

  3. Dave Williams | | #3

    You have a house nearly identical to mine, which was built in Pittsburgh in 1951. Same walls, same pitiful insulation, but good bones.

    Over the years, I've had cellulose dense-packed into the walls, which made a significant difference. Also I added solar blocking film to all the non-northern windows, which made a huge difference in summertime.

    I got rid of the old useless attic insulation and put in 12 inches of cellulose, after extensive air sealing. Big difference.

    Do you have an integral garage? If so, is there any insulation above it?

    Bathrooms with a lot of tile? Radiant heaters made a huge difference in comfort here.

    Soffit vents I'd think would make a huge difference as well. They're next on my list.

    Ultimately I'm aiming for a hot water radiant heating system, and a high flow AC system.

  4. GBA Editor
    Martin Holladay | | #4

    SlateRun,
    I'm going to have to disagree with "DIY Owner" and Dave. I don't know why they are recommending cellulose on the attic floor, when your attic is full of ductwork. I agree with you: If you can afford it, it makes more sense to move the thermal boundary to the sloped roof, so that your attic becomes part of your conditioned space. For more information on this approach, see Creating a Conditioned Attic.

    It's hard to do much with your walls, since you have block walls with brick cladding and only 3/4-inch of space between the strapping.

    If I were you, I would perform air sealing work in the basement, and then insulate the basement walls. For more information on this work, see these articles:

    Air-Sealing a Basement

    How to Insulate a Basement Wall

    When it comes to the windows, I would assess them individually. Unshaded west-facing windows (if there are any) are contributing to your air-conditioning load, so you might think about ways to shade them. If there are functional problems with some of the operable windows, you might consider upgrading to new windows with better glazing and weatherstripping, although this work won't yield enough energy savings to justify the investment.

  5. Dave Williams | | #5

    Woops hadn't caught the block walls, which I only have in the basement. My upper floor is framed, so I had 3.5 inches of space to fill with cellulose behind the rocklath.

    Wouldn't the deep-dish retrofit be a good option for the OP?

  6. GBA Editor
    Martin Holladay | | #6

    Dave,
    I assume that you are making a jocular reference to a "deep energy retrofit," a term that has no technical definition. The usual meaning is "an energy retrofit job that costs buckets and buckets of money."

    SlateRun didn't brag about his big fat bank account, so I'm going to assume that SlateRun prefers to limit the work to cost-effective options.

  7. SlateRun | | #7

    Thanks for all the answers so far. You're right, Martin, money is always a concern, in this case it's less about availability of funds, and more about not wasting it on extreme measures with questionable returns. Which leads to more questions.

    Is there any way to gauge the efficiency gain of entirely removing the AC system from the attic space and replacing it with either a basement ducted unit, or spit systems? If it stays in the attic, at some point I will have to re-do just about everything. The new unit is perched on scrap wood piles across the floor joists. The plenums are just two sorry boxes made of ductboard, and the distribution is ridiculously long runs of old 8" flex that is falling apart. In this fairly mild climate, would $3K worth of ductwork upgrades including insulating everything, be a better investment that spending $8K to install a whole new setup in the basement? Any idea what the energy loss penalty is for having attic HVAC over basement in any given situation, new construction, or otherwise?

    Obviously a conditioned attic with closed cell foam would probably be best, but tough to justify, cost wise, if repairing the ductwork, removing the old batts, air sealing the lid, and blowing r-50 cellulose would be 70-80% as effective in reducing energy consumption.

    I'm actually a retired home builder, so none of this is totally unfamiliar to me, I'm just not well versed in patching up older places. When we relocated to the wife's prefered retirement location, the possibility of me building another new place for us was pretty slim, due to everything from a lack of available lots, to extreme costs involved with local regulations. OTOH, owning an uninsulated plastered house with solid masonry walls, and an HVAC system that looks to have been installed by two monkeys and a dog, is not what I expected to be dealing with at this point of my life, LOL.

  8. Expert Member
    Dana Dorsett | | #8

    "Is there any way to gauge the efficiency gain of entirely removing the AC system from the attic space and replacing it with either a basement ducted unit, or spit systems?"

    Yes- it's not a simple process and unless duct leakage, differential pressure between the attic & conditioned space while the air handler is running, as well as blower-door measurements are all factored in, the estimates are pretty crude. A Manual-J load calculation can give you the approximate duct losses from which you can infer the total annual energy needed to cover it but it's a really squishy number unless measuring the actual leakage, not just the surface losses.

    In general, if there is room in the basement to put it all in the basement, getting rid of the duct gains/loss and the parasitic air handler driven infiltration it's likely to take between 0.5-1.5 tons of actual LOAD off the air conditioning peaks, and even more off the heating load. (Mind you this estimate isn't science- it's a WAG.) With the ducts an air handler in an insulated conditioned basement rather than about the insulation in an unconditioned attic the energy use consequences of duct losses are very small by comparison.

    "Obviously a conditioned attic with closed cell foam would probably be best, but tough to justify, cost wise..."

    Closed cell foam in the attic isn't the go-to solution at all, since you don't need the low vapor retardency in an attic. If insulating without venting at the roof deck you don't need more than 30% of the total R to be closed cell foam to meet IRC prescriptives in zone 4A. With a vented solution you don't need any closed cell foam. Open cell foam on the underside of the roof deck with rigid foam above can be cheaper & better, if re-roofing is part of the rehab. The $2 per square foot you'd pay for 2" of closed cell buys you 6" of open cell foam, which is a full cavity fill for full-dimension 2x6 rafters (!). Using 3-4" reclaimed roofing foam above the roof deck (at 25-35% the cost of virgin stock goods) can take the sting out of the foam budget, but it's still quite a bit more expensive than an attic floor full of fluff.

    With the mechanicals in the basement it's easier & cheaper air-seal the attic floor and pile-on cheap fluff rather than expensive foam or complicated vented-cathedralized ceiling solutions. Replacing the system installed by the simian & canine crew while leaving it the unconditioned attic wouldn't be nearly as good an investment.

    The walls could be insulated on the exterior to avoid having to gut the walls and giving up interior space. With the thermal mass of brick on the interior side of continuous insulation it qualifies as a "mass wall", and will meet current IRC 2015 code-minimum with 2" of EPS, 1.5" of polyiso, or 2" of rigid rock wool- all it takes is R8 of continuous insulation. A spray applied weather resistant barrier (WRB) on the exterior brick is likely to improve air tightness better than with other types of WRB. The foam can be mechanically strapped in place with 1x4 furring through-screwed to the brick, with new siding fastened to the furring. Using reclaimed foam can make this approach VERY cost-competitive with full gut interior side solution, but even virgin stock Type-II EPS would run under a buck a square foot for the insulation. This reclaimed foam pallet of 61 sheets of 4x8 1.5" polyiso is 1900 square feet of R9, which is probably enough foam to do the whole exterior of your 1200' house, and at the advertised price it's less than 4 cents per R-foot, (which is cheaper than low density batts !):

    https://harrisburg.craigslist.org/mat/6167611919.html

    The furring, masonry screws, siding and sill /trim details will end up costing quite a bit more than the insulation, but you should be able to run those numbers.

    Surplus & reclaimed foam deals come & go, but there are foam reclaimers that will drop-ship quantities that large (for a price), and it's still pretty cheap.

    There are a lot of details to work out around the window & door openings, but with a spray applied WRB any pre-existing flashing is probably already directing bulk water to the right place. With 2" of rigid foam, 1x4 furring plus siding it's adding about 3.5" to the thickness of the walls. That presents an issue for some minimal or zero-overhang roofs, so think out those details clearly before diving in.

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